SheHateMe

From what I have been told in the past, when building a sealed box your suppose to put something in the bottom of it to fill up a bit of space, such as cotton, or even old sweaters. Is this true? I remember when I bought my 2 older kicker CVR's from a friend thats really into car audio, there was a cotton type object in the bottom of each chamber.

rastanearian

This is not necessary, as the frequencies a sub operates at are usually much lower than any internal resonances the cabinet may have. Stuffing the box is really only for mid-woofers and mids.

92zed34

iTrader: (4)

I thought that the "fill" was there to trick the woofer into producing lower freq by making the box seem bigger to the woofer.

MTT

iTrader: (17)

good read HERE

rorybreaker

good reference MTT. Stuffing a box produces an adiobadic reaction when the woofer compresses the internal volume (thermal rise due to compression of a gassious medium). There is however another, simpler benifit to laying fiberglass bat/ ect. upon the internal surfaces of a box, the "internal resonance". You can cut nasty beta notes and unwanted box resonance by insulating at least one of each oposite side of a box. For this reason throwing a sweater on the bottom of a box might cut out unwanted high notes produced by reflection inside the box, but not in an acurate way.

As for wool: yes loose, unwoven wool has leant to better compression differences than fiberglass or even dacron. A close second to it is loose cotton.